JP2012236305A - Liquid ejecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejecting apparatus capable of improving the quality of a print image by making an appropriate tension adjustment when transporting elongated continuous media to a print location.SOLUTION: The liquid ejecting apparatus includes: a tension roller 11 that is provided downstream the print location in the media transporting direction to impart tension to the media 4 transported to the print location; and a torque limiter 19 for making a rotation torque of the tension roller 11 variable to adjust the tension imparted to the media 4.

Description

  The present invention relates to a liquid ejection apparatus such as an ink jet recording apparatus.

The applicant of the present invention, for example, in an inkjet plotter, transports a long continuous cloth medium on the platen to a printing position facing the inkjet head so that distortion and wrinkles do not occur. A pair of feed rollers is provided on the upstream side in the conveying direction, and a tension roller is provided on the downstream side. The tension roller and the feed roller are rotationally driven in synchronization in the same direction. At this time, a device has been proposed in which tension is applied in the conveyance direction of the cloth medium by driving the tension roller so that the circumferential speed of the tension roller is about 1 to 3% higher than the circumferential speed of the feed roller (Patent Document 1). .
Alternatively, the medium is conveyed from the supply roll to the printing position on the platen via the upstream tension bar, and the medium is conveyed from the platen via the downstream tension bar to be wound on the winding roll while being tensioned.

JP 2000-203752 A

  In the case of using a medium such as cloth, which has higher elasticity than the above-described medium such as plain paper, resin sheet such as PP (polypropylene), PET (polyethylene terephthalate), etc., the peripheral speed difference between the tension roller and the feed roller Even if it is provided, there is a possibility that the elongation of the medium absorbs this and sufficient tension is not applied at the printing position. Even if a certain tension is applied to the medium, there is a possibility that the image quality of the printed image is deteriorated due to the elongation in the transport direction of the medium.

  Also, even if tension bars are provided on the upstream side and downstream side of the platen to apply tension to the media, in the case of media such as highly stretchable cloth, sufficient tension is not applied at the printing position on the platen. There is a fear.

  An object of the present invention is to provide a liquid ejection apparatus that solves the above-described problems and improves the image quality of a printed image by performing appropriate tension adjustment when transporting a continuous continuous medium to a printing position. It is in.

  In order to solve the above problems, a liquid ejection apparatus according to the present invention has the following configuration. In other words, a liquid ejection device includes a liquid ejection head that ejects liquid onto a long continuous medium to form a print image, and a transport device that continuously transports the media to a printing position facing the liquid ejection head. A device that is provided downstream of the printing position in the medium conveying direction and that applies tension to the medium conveyed to the printing position, and the tension applied to the medium by the tension applying means can be adjusted. And a tension adjusting means.

  According to the above configuration, even when a highly stretchable medium such as a woven fabric or a non-woven fabric is used, tension is provided on the downstream side of the print position in the transport direction of the medium that is transported to the print position by the transport device on the platen. Since it is pulled and conveyed by the means, the slack of the media at the printing position can be reduced. Further, since the tension adjusting unit can finely adjust the tension applied by the tension applying unit so that the optimum tension is applied at the printing position according to the type of the medium, the image quality of the printed image can be improved.

In the present invention, the tension adjusting means includes a tension roller as the tension applying means, a roller shaft of the tension roller, and a connecting portion that connects a motor shaft of a drive motor as a drive source for driving the tension roller. A torque limiter provided on the medium, and the tension acting on the medium may be adjusted by changing the rotational torque transmitted to the tension roller by the drive motor.
According to this, by using a general-purpose torque limiter, the mechanical structure can be simplified and tension adjustment can be realized at low cost and in a small space.

In the present invention, the tension adjusting means may be a friction clutch, and may adjust a tension applied to the medium by adjusting a frictional force of a friction part.
Thereby, tension adjustment can be realized at low cost by using a general-purpose mechanical clutch as the tension adjusting means. As the tension adjusting means, instead of the friction clutch, the torque limiter, or the like, the clutch is configured so that the motor current value is controlled to idle to reach a predetermined torque, or the motor torque is monitored and the predetermined torque is monitored. A configuration in which the electromagnetic clutch is idled when the torque is reached, or tension adjustment by a non-contact force (magnet coupling) may be used.

In the present invention, it is preferable that the tension roller has a circumferential surface that is in contact with the medium and is roughened by metal spraying.
According to this, especially when the medium is a cloth medium, the biting with the tension roller is improved, so that the tension can be easily adjusted.

In the present invention, the transport device is provided on the upstream side in the media transport direction from the printing position and transports the media to the print position, and provided on the downstream side in the media transport direction from the platen. A tension roller that applies tension to the medium conveyed to the position may be provided.
Thereby, tension can be reliably applied to the medium by the driving roller on the upstream side and downstream side of the platen, so that the image quality at the printing position can be improved.

In the present invention, an upstream tension bar that applies tension to the medium fed from the supply-side roll to the printing position, and a downstream tension that applies tension to the medium that is wound from the platen to the winding-side roll. And a bar.
This removes the slack of the media on the upstream side of the platen in the media transport direction and the downstream side of the media transport direction, and improves the media slack removal effect at the printing position facing the platen by the tension roller as a synergistic effect.

  According to the present invention, it is possible to provide a liquid ejecting apparatus in which the image quality of a printed image is improved by performing an appropriate tension adjustment when transporting a long continuous medium to a printing position.

It is a schematic diagram of an inkjet recording device. It is explanatory drawing which shows a conveying apparatus. FIG. 6 is an enlarged view of a printing position using a cloth medium and a perspective view of a tension adjusting unit. It is an enlarged view of a printing position according to another example.

  Hereinafter, embodiments of a liquid ejection apparatus according to the present invention will be described in detail with reference to the drawings. In the following, an ink jet recording apparatus will be described as an example of a liquid ejection apparatus together with the configuration of the transport apparatus. Further, the main scanning direction indicates the medium (medium) transport direction (X-axis direction), and the sub-scanning direction indicates the direction in which the carriage reciprocates perpendicular to the main scanning direction (Y-axis direction).

  FIG. 1 is a perspective view showing the appearance of the ink jet recording apparatus. As shown in the figure, the inkjet recording apparatus 1 uses, for example, a large and long roll sheet (in this embodiment, cloth, cloth, etc.) as a medium (printing medium). The media 4 fed from the supply roll 3 wound around the feed shaft 2 is conveyed to the platen 6 via the upstream tension bar 5.

  The platen 6 is provided with a transport device 7, and the medium 4 is transported by the transport device 7 to a printing position facing the ejection head 8 in the main scanning direction. The ejection head 8 is mounted on a carriage 9, and the carriage 9 is provided so as to be able to reciprocate along a Y-axis direction support member (Y bar) 10 provided in the sub-scanning direction (media width direction). . Printing is performed by ejecting ink liquid onto the medium 4 while the carriage 9 moves in the sub-scanning direction. When printing is performed, the medium 4 is sent by the conveying device 7 in the main scanning direction, and the carriage 9 is moved. The next printing operation is started after scanning.

  In addition, a concave ink receiving member 15 (see FIG. 3) may be provided in a part of the platen 6 facing the ejection head 8 because the ink is transmitted (back through) in the case of cloth media. .

  Further, on the back surface of the platen 6 that guides the conveyance while supporting the medium 4, a heater 16 (see FIG. 4) for improving the fixing property of the ink, and a media guide (not shown) that suppresses lifting of both sides of the medium 4. May be provided.

  The medium 4 after printing is sent downstream by a tension roller 11, and is wound as a winding roll 14 on a winding shaft 13 through a downstream tension bar 12.

As shown in FIG. 2, the transport device 7 includes drive rollers 7 a provided on both sides in the width direction of the medium 4. The driving roller 7 a is provided in contact with the back side of the medium 4. As the drive roller 7a, a spike roller having a metal piece projected on the surface by cutting is suitably used for cloth media. The drive roller 7a is provided at equal intervals at a plurality of locations in the longitudinal direction of the drive shaft 7b. A pulley 7c is provided at the end of the drive shaft 7b, and is connected to a motor pulley (not shown) provided on the motor shaft of the drive motor 7d by a timing belt 7e.
As shown in FIG. 4, the transport device 7 may include a driven roller 7 f that sandwiches the drive roller 7 a and the medium 4.

  A pair of media encoders 7 g are provided on both sides of the media 4 on the downstream side in the media transport direction from the drive roller 7 a. Each media encoder 7g detects the transport amount of the media 4, and a detection signal is input to a motor drive control unit (not shown). The motor drive control unit compares the drive pulse output to the drive motor 7d with the detection signal (detection pulse) of the media encoder 7g to determine whether the media 4 is being transported in parallel with the transport direction or the media 4 It is possible to know the conveyance state as to whether it is inclined toward one of the width directions. Then, the motor drive control unit performs acceleration / deceleration control (feedback control) so that the drive speed of the drive roller 7a provided on both sides of the medium 4 is corrected according to the inclination of the medium 4 with respect to the conveyance direction. To do.

  In FIG. 3A, the tension roller 11 is formed in a rough surface on the peripheral surface of a metal roller (made of stainless steel or aluminum) by metal spraying. Thereby, when the medium 4 is a cloth medium, the biting with the tension roller 11 is improved, so that the tension can be easily adjusted. Note that the media 4 other than cloth, such as a resin sheet, may be a roller made of rubber or resin, without necessarily having a rough surface.

  In FIG. 3B, the roller shaft 11 a of the tension roller 11 is rotatably supported on the sheet metal 17 and is connected to the coupling shaft 18 a via the coupling 18. A torque limiter 19 (tension adjusting means) is connected to the coupling shaft 18a. A motor shaft 20 a of a tension roller drive motor 20 is connected to the torque limiter 19. When the adjustment dial 19a is rotated, the torque limiter 19 changes the biasing force of the coil spring provided in the torque limiter 19 and adjusts the friction force between the friction plates so as to adjust the tension acting on the media 4. It has become.

  According to the above configuration, even when a highly stretchable medium 4 such as a woven fabric or a non-woven fabric is used, a rough tension is applied to the upstream and downstream sides of the platen 6 by the tension bars 5 and 12. Since the torque limiter 19 can be finely adjusted by the tension roller 11 so that the optimum tension is applied according to the type of the medium 4 on the downstream side in the transport direction of the print position on the print position 6, the image quality of the print image can be improved.

  The tension adjusting means may be a clutch using a contact force such as a friction clutch or a torque limiter, or a configuration in which the motor current value is controlled to idle to reach a predetermined torque, or the motor torque is monitored to reach a predetermined torque. A configuration in which the electromagnetic clutch is idled or tension adjustment by a non-contact force (magnet coupling) may be used.

  FIG. 4 is an enlarged view of a printing position according to another example. In the present embodiment, a plurality of rows (four rows) of ejection heads 8 are provided in the medium conveyance direction, and the platens 6 are linearly arranged facing the ejection heads 8. The concave groove 6a formed on the back surface side of the platen 6 incorporates a heater (heating wire) 16, and the medium 4 is sucked onto the platen 6 by a suction device (not shown). When ink droplets ejected from the ejection head 8 land on the medium 4, they are dried by a heater 16 that heats the platen 6.

On the upstream side of the platen 6 in the medium conveyance direction, a conveyance device 7 that conveys the medium 4 with the drive roller 7a and the driven roller 7f sandwiched therebetween is provided. Further, a tension roller 11 connected to the torque limiter 19 described above is provided on the downstream side of the platen 6 in the medium conveying direction.
With such a configuration, tension can be reliably applied to the medium 4 on the upstream side and downstream side of the printing position on the platen 6, so that the image quality can be improved.

  As described above, even when a highly elastic medium 4 such as a woven fabric or a non-woven fabric is used, the medium 4 conveyed on the platen 6 to the printing position by the conveying device 7 is provided downstream in the conveying direction of the printing position. Since the tension roller 11 is pulled and transported, the slack of the medium 4 at the printing position can be reduced. Further, by making the rotational torque of the tension roller 11 variable by the torque limiter 19, fine adjustment can be performed so that an optimum tension is applied at the printing position according to the type of the medium 4, so that the image quality of the printed image can be improved. it can.

  Further, the looseness of the medium 4 on the upstream side in the media conveyance direction and the downstream side in the media conveyance direction of the platen 6 is removed by the tension bars 5 and 12, and the slack removal effect of the media 4 at the printing position facing the platen 6 by the tension roller 11 is obtained. Improve as a synergistic effect.

  Further, by using a general-purpose torque limiter 19 as tension adjusting means, the mechanical structure can be simplified and tension adjustment can be realized at low cost and in a small space. Furthermore, since the peripheral surface of the tension roller 11 that contacts the medium 4 is formed into a rough surface by metal spraying, especially when the medium 4 is a cloth medium, the biting with the tension roller 11 is improved. This makes it easier to adjust the tension.

  DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Feeding shaft 3 Supply roll 4 Media 5 Upstream tension bar 6 Platen 6a Concave groove 7 Conveying device 7a Drive roller 7b Drive shaft 7c Pulley 7d Drive motor 7e Timing belt 7f Driven roller 7g Media encoder 8 Discharge head 9 Carriage DESCRIPTION OF SYMBOLS 10 Y-axis direction support member 11 Tension roller 11a Roller shaft 12 Downstream tension bar 13 Winding shaft 14 Winding roll 15 Ink receiving member 16 Heater 17 Sheet metal 18 Coupling 18a Coupling shaft 19 Torque limiter 19a Adjustment dial 20 Tension roller drive Motor 20a Motor shaft

Claims (6)

A liquid ejection apparatus comprising: a liquid ejection head that ejects liquid to a continuous medium in a long shape to form a print image; and a transport device that continuously transports the medium to a printing position facing the liquid ejection head. There,
Tension applying means for applying tension to the medium that is provided downstream of the printing position in the medium conveying direction and is conveyed to the printing position;
A liquid ejecting apparatus comprising: a tension adjusting unit capable of adjusting a tension applied to the medium of the tension applying unit.   The tension adjusting means is a torque limiter provided at a connecting portion for connecting a tension roller as the tension applying means, a roller shaft of the tension roller, and a motor shaft of a drive motor as a drive source for driving the tension roller. The liquid ejecting apparatus according to claim 1, wherein the tension acting on the medium is adjusted by changing a rotational torque transmitted to the tension roller by the drive motor.   The liquid ejecting apparatus according to claim 1, wherein the tension adjusting unit is a friction clutch and adjusts a tension applied to the medium by adjusting a frictional force of a friction portion.   4. The liquid ejection device according to claim 1, wherein a circumferential surface of the tension roller that is in contact with the medium is formed into a rough surface by metal spraying. 5.   The transport device is provided on the upstream side in the media transport direction from the print position and transports the media to the print position. The transport device is provided on the downstream side in the media transport direction from the platen and transported to the print position. The liquid ejecting apparatus according to claim 1, further comprising a tension roller that applies tension to the medium. An upstream tension bar for applying tension to the media fed from the supply roll to the printing position;
6. The liquid ejection device according to claim 1, further comprising: a downstream tension bar that applies tension to the medium that is wound from the platen to the winding-side roll.

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